Method of hardening and tempering.



J. PATTEN.

METHOD OF HARDENING AND TEMPERING.

APPLICATION FILED AUG 15, 1912. 1 11 2,087, Patented Sept. 29, 1914.

5 SHEETS-SHEET 1.

J. PATTEN.

ME HHHHHHHHHH DENING AND T EEEEEE RING.

APPLICATION FILED AUG 15.1912. 1 1 1 2,087 Patented Sept. 29, 1914.

. 5 SHEETS SIIIJEI 12v Z Z: gs A J PATTBN.

METHOD OF HARDENING AND TEMPERING.

APPLIQATION FILED AUG 15, 2912.

1 ,1 1 2,08? Patented Sept. 29, 1914.

SWIM/whoa 2&4 02m;

J. PATTEN.

METHOD OF HARDENING AND TEMPERING= APPLIGATION FILED AUG 15 1912. 1, 1 1 2,087, Patented Sept. 29, 1914.

5 SHEETSSHEET 4,

J. PATTI-1N.

METHOD OF HARDENING AND TEMPBRING.

APPLIOATION FILED AUG 15,1912. 1 I 1 1 1 2,087, Patented Sept. 29, 1914.

K 5 SHEETS-SHEET 5;

JOHN PATTEN, OF BALTIMORE, MARYLAND.

METHOD OF HABDENIN G AND TEKI'EBING.

Specification of Letters Patent.

Patented Sept. 29, 1914.

Application filed August 15, 1912. Serial No. 718,8!8.

To all whom it may concern:

Be it known that I, JOHN Pa'rran, a citizen of the United States, residing at Baltimore city, Maryland, have invented certain new and useful Improvements in Methods of Hardening and Tempering, of which the following is a specification.

My present invention relates to a method and apparatus for hardening the surface of bodies of steel or other metal which may be hardened by heating and rapidly cooling.

The invention is applicable to the hardening of either plain or cylindrical surfaces or the edges of cutting tools such as the various kinds of shears.

It is particularly adapted for hardening the interior surfaces of guns or engine c L inders although it may be applied genera ly to metal surfaces, and particularly to sur. faces of thick metal bodies which will quickly absorb the heat and which therefore do not require artificial cooling. Thus it is well adapted for hardening the surfaces ofheavy guns, railroad rails and other articles having considerable mass.

In the preferred form of the invention I arrange an electric arc to impinge upon the surface to be hardened and then move the surface and the are relatively until the arc has traveled over the entire surface to be treated. While by this method a single restricted spot of the metal is treated at a time the relative movement of the arc and surface may be rapid and I can treat and harden large surfaces very rapidly. I may use two electrodes adjacent the surface to be treated and pass an electric current through them, directing the are against the surface by a magnet or other suitable means, or I may include the metal body to be treated in the circuit and as one of the electrodes.

The particular electrical apparatus involved may be greatly varied and any suitable means may be used for supplying the necessary electric current, regulating the same and regulating the feed of the carbon electrodes used in creating the are as they are consumed.

In hardening dies and other metallic articles it has been heretofore customary to heat the whole of the die to the required temperature and then apply the cooling agent. The effect of this is to cause minute cracks to occur in the surface of the metal and also to distort or warp the shape of the object. By employing my method, however, these disadvantages of the prior methods of hardenmg and tempering are eliminated owin to the fact that only a small spot is heate at a t1me and the heat only penetrates to a slight depth. The ex ansion of the spot which is heated in ta en up by the compression of the surrounding. metal so that the article s a whole is not distorted, and cracks are avoided. In carrying out my invention I may also employ a cooling agent to cool the heated spot immediatel after the arc has heated the same. For t e purpose of thus cooling the surface I use a suitable pipe which delivers the cooling agent to the surface immediately following the passage of the arc and the cooling agent may be water, or any other suitable liquid or gas. It is frequently desirable to use inert gas for this purpose as the contact of air with the heated surface would have a tendency to oxidize a part of the metal, and I avoid this oxidation by projecting a jet of the inert gas against the heated surface so that the air is driven awa Carbon dioxid or preferably the gases 0 combustion from an ordinary steam boiler furnace may be employed, although, of course, I do not wish to be limited to the use of these particular gases.

For the purpose of illustrating the use of my improved method of hardening and tempering I have shown several forms of appa ratus adapted to harden and temper objects of various shapes, but it will be understood that the method herein claimed is not limited to these forms of apparatus as it will be obvious that various other forms may be devised. v

In the drawings, Figure 1 is a longitudinal section showing an apparatus suitable for hardenin the interior of the gun or long tubular ody. Fig.2 is'a section on the line 22 of Fig. 3. Fig. 3 is a transverse section on the line 3-3 of Fi 1. Fig. 4 is an end elevation of certain 0 the parts shown in Fig. 1. Fig. 5 is a longitudinal section through .an apparatus for hardening and tempering comparatively short tubular bodies, such as engine cylinders. Fig. 6 is a fragmentary end elevation of certain parts shown in Fig. 5. Fig. 7 is an elevation with certain parts shown in section of an apparatus for tempering and hardening the exterior of cylindrical bodies. Fig. 8 is a section on the line 8-8 of Fig. 7. Fig. 9 illustrates a modified form of electrodes which may be used in place of those shown in the other views. Fig. 10 is a perspective view of an apparatus for hardening and tempering a flat surface.

Referrin to Fig. 1, 15 indicates the gun or tube to e hardened. A support or rest for the tube 15 is shown at 16 and has connected therewith a conductor 17. Fitting within the tube and adapted to be moved longitudinally thereof is a head 18 which is secured on the end of a feed tube or rod 19 in any suitable manner as by means of the set screw 20. The outer end of the feed tube 19 is mcured to a carriage 21 in any preferred manner as by means of a set screw 22, and this carriage ma be moved to feed the tube back and forth an suitable mechanism such as that emp oye to move the carriage of the ordinary lathe. The head 18 is provided with an opening 23 through which projects an electrode 24, preferably of carbon, this electrode being secured in a holder 25 in an suitable manner. The holder 25 is slidab y arranged in a suitable casing 26 which is supported on and insulated from the feed tube 19, a suitable insulator 27 being provided for this purpose. A rack 28 is secured to the holder 25 and a pinion 29 arranged in a suitable recess in the casing 26 has its teeth in engagement with the rack 28 and is secured to the end of a shaft 30 which extends longitudinally through the feedtube 19 and has its outer end supported in a bearing 31 which is insulated from the tube 19 by means of a suitable insulator 32. A bell crank 33 is secured to the outer end of the shaft 30 and one arm of this bell crank is provided with a handle 34 and the other arm is operatively connected with a plunger 35 which is adapted to be reciprocated by a feeding mechanism 36 of any suitable construction. The feeding mechanism 36 may be of any of the constructions commonly employed for feeding the carbons in arc lamps and as the detailed construction of this mechanism forms no part of the present invention it has been deemed unnecessary -to illustrate and describe the same. At 37 I have indicated a source of electricity and one terminal of this source has connected therewith the conductor 17 and the other terminal is connected with a rl'ieostat 38. The rheostat 38 is connected with the feeding mechanism 36 by a conductor 39, an ammeter 40 being provided for the purpose of indicating the current.

From the above it will be seen that the current from the source of electricity 37 will pass through the rheostat 38, the feeding mechanism 36, the plunger 35, the bell crank 33 and shaft 30 to the holder 25 of the electrode 24. One end of the electrode 24 is spaced a slight distance from the inner surface of the tube 15 so that an arc will be formed .at this point, the current passing from the electrode through the metal of the tube to the conductor 17 and thus returning to the source 37. F or the purpose of cooling the surface immediately after the same has been heated by the are I have provided a tube 41 which is carried by the tube 19 and is provided with a nozzle 42 arranged to project a jet of the cooling medium onto the surface immediately after the passage of the arc thereover. It will thus be seen that the jet of cooling medium will drive the air away from the heated spot and if an inert gas is used as the cooling medium oxidation of the cooling metal will be prevented.

In the operation of the mechanism the tube 15 is rotated and the head 18 is radually fed through the tube so that t e are covers the surface which it is desired to harden and temper, the path of the are relative to the tube being of helical form.

The feeding mechanism 36 is preferably of the type which is adapted to maintain constant current through the circuit by varying the distance of the end of the electrode 24 from the surface over which it is being passed. As will be readily understood this is accomplished by rocking the bell crank 33 and the shaft 30, thereby turning the ear 29 and movin the rack 28 and the ho der 25. By providing the handle 33 the current through the circuit may also be varied by the operator independently of the mechanism 36. 7

Referring to Figs. 5 and 6 it will be seen that I have illustrateda slightly different form of apparatus for hardening the interior of comparatively short tubes, such as engine cylinders, etc. Referring to Fig. 5, 43 indicates the face plate of an ordinary lathe to which the tube 44 is secured by means of the jaws 45. The outer end of the tube 44 may be supported in a suitable rest 46 and a head 47 is arranged on the interior of the tube and adapted to be moved'longitudinally thereof by means of a rod or tube 48 which is secured to the usual carriage 49, this carriage being moved back and forth on the bed of the lathe by the usual feed screw 50. A bracket 51 is secured to the head 47 by means of suitable bolts 52 and insulated therefrom. A bell crank 53 is pivoted to the bracket 51 and also to an electrode holder 54. A link 55 also connects the holder 54 with the bracket 51, the arrangement of this link and the bell crank 54 be- .ing such that the holder 54 has a parallel motion. An electrode 56 is secured in the holder 54 in any suitable manner as by having the holder split along one side and clamped together by means of bolts or screws passing throu h openings in the lugs 57. The bell crank 53 is provided with a counterweight 58 which balances the weight of the holder 54 and the electrode 56 and the rod 59 is pivotally connected with connected together by an insulator 62. The

bracket 61 also carries a feeding mechanism $3 forthe electrode 56, this feeding mechanism being of any suitable construction and preferably of the type commonly used in arc lamps to feed the carbons. Electric ity is passed from 'a'source 64 through a rheostat 65, the feeding mechanism 63 and conductor 66 to the electrode holder 54 and from the latter through the electrode 56 and across the space between the end of the latter and the surface 'of the tube 44. The current passes to the rest 46 and through the conductor 67 to the source 64. A nozzle 68 is secured to the end wall of the head 47 and is in communication with the interior of the tube 48, the latter being supplied with a cooling agent from any suitable source.

An ammeter (39 is arranged in the circuit for the purpose of indicating the current which is flowing therein.

The operation of this apparatus is similar to that shown in Fig. 1, the face plate 43 of the lathe being rotated and carrying with it the tube 44, and the head 47 being fed through the tube by means of the carriage 49 and the feed screw 50, and the arc'traveling in a helical path relative to the tube 44. The current is maintained constant by the feeding mechanism 63 which, as will be readily understood, is adapted to vary the space between the end of the electrode 56 and the inner surface of the-tube 44.

The two forms of apparatus just described are for hardening and tempering the interior surface of the tube. For the purpose of employing my improved method for hardening the exterior surface of a cylindrical body, the apparatus shown in Fig. 7 may be used. This apparatus consists preferably of an ordinary lathe; the head-stock being shown at and the tail-stock at 71. Arranged in the lathe in the usual manner I have shown a reamer having the cutting head 72 and the cylindrical shank 73, the reamer bein secured to the face plate 74 of the lathe y means of a dog or clamp 75. The carriage of the lathe, shown at 76 is moved longitudinally of the bed of the lathe by 'means of the usual feed screw 77. A bracket 78 is secured to the carriage 76 and supports a feeding mechanism 79 for the electrode 80, this .eeding mechanism being preferably 9f the type commonly employed in arc lamps for feeding the carbons thereof. A nozzle 81 may be secured to the feedingmechanism 79 and supplied with a suitable cooling agent by means of a tube 82. A source of electricity 85 is provided, the current from this source passing through a rheostat 86 and a conductor 87 to the feeding mechanism 79 and from the latter through the electrode to the shank 73 of the reamer or other articlebeing treated. The current passes through the article to the tail-stock of the lathe'and from the lattor it returns to the source through a conductor 88. An ammeter '89'may be provided to indicate the amount 'of' current flowing through the circuit. In theoperation of this apparatus the articleis rotated in the usual manner and the electrode moved lengthwise of the article by means of the feed screw 77. In this way the arc is made to traverse the surface of the article in a helical'path and as much of the surface as is desired may be treated. For the purpose of treating acutting edge such as one of the edges of the reamer head 72 I have shown the carriage 76 and the bracket 78 and the mechanism carried thereby in a dotted position in Fig. 7. It will be understood that the apparatus may be identical with that just described with the exception that in treating the cutting edge the article is not rotated. In this case only the feed screw 77 will be operated so that the electrode 80 will travel lengthwise of the article ovei the cutting edges thereof; IV hen an article, such as a reamer having spirally arrangedcutting edges, is to be treated it will be observed that the same apparatus may be used'except that' in this case the article will be rotated suiiiciently in relation to the longitudinal feed to accurately follow the cutting edge. In Fig. 8 I have shown the relation of the electrode 80 to the cutting edges of the reamer head 72 in hardening and tempering the same.

In Fig. 10 I have illustrated an apparatus for hardening a fiat surface. In this apparatus I employ a suitable bed or support90 in which is arranged the article 9l t0-be treated. The bed 90 is illustrated as a trough which is adapted to contain a cooling agent, such as water, the water preferably rising to a point just below the top surface of the article to be treated so that the larger portion of the article will be submerged.

The bed is provided with ways 92 on the opposite sides thereof and a carria e 93 is arranged to be moved back and fort along these ways. A head 94 is slidablyarranged on the-carriage 93 and is moved back and forth thereon transversely of the ways 92 by means of a suitable screw 95 which may :be operated by a crank 96. The carriage 93 is moved along the ways 92 by means of feed screws 97 and 98 which are preferably operated from a common shaft 99 by means of the bevel gears 100. The head 94 carries an electrode feeding mechanism 101 for an electrode 102 which has its lower end arranged slightly above the article 91 so that an arc will be formed between the end of the electrode and the article when a current is passed through the electrode. A bracket 10a is carried on the head 9% andlsupports the conductor lOtaudialso. the pipe 105 for "the cooling agent, the latter terminating in ductor 104 to the feeding mechanism 101 and from the latter through the electrode 102 to the article 91. From the article 91 the current returns to the source by means of a COl'ldtlCtOl'lOi). An amuieter 110 may be providedin the circuit for the purpose of indicating the amount of current flowing,

lu Fig. 9 I have shown a modified form of electrode in which two carbons 111 and 11; are en'iploycd, the are being formed across the adjoining ends of these carbons. Forthc purpose of directing the are against the surface 113 to be treated either a blast of air or a magnet 11% may be employed, these being connnen devices for deflecting an arc.

Having thus described the invention What is claimed as new is:

g 1. The method of hardening a cylindrical surfaeeof a piece of metal which consists in'applyingan electric arc to the surface and relatively rotating the are and surface,

and also imparting a relative axial movement until the entlre surface to be treated has been traversed by the are;

1 The -method of surface hardening a cylindrical surface of a pieeeof metal which consists in subjecting the surface to an elec; tric are, and imparting a rotary movement to-the surface and an axial movement to the are whereby the entire cylindrical surface a be treated. I a

'3. The methodof surface hardening a piece of metal which consists in applying an electric arc thereto, causing. themetal and are to travel relatively, and rapidly absorbing the heat from the. pathof-the arc in the rear thereof.

l. The method ofsurface hardening a a piece of metal which consists in applying an electric arc thereto, causmgthe metal and are to travel relativelv and ra )idl eoolin the surface in the path of the are immedi- .ately after the passage of the are.

The method of surface hardening a piece of metal. which consists in applying an electric arc thereto, causing the metal and are to travel relatiyely, and rapidly cooling the surface in the path of the are and imn'iediately in the rear of the are by directing thereon a stream of cold fluid.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN PATTEN.

. \Vitnesses:

An'rnUn-L BRYANT, B. M. KENT. 

